You can locate required books for your class through the bookstore. At the bookstore site, go to Books>Textbooks & Course Materials and then enter the appropriate campus/term/department/course/section information to generate your book list. Your class syllabus should also have this information.
If your instructor has placed books for your class on course reserves, you can find that information via the Library Course Reserves link for the course in Blackboard.
The MC Library is building a collection of Textbooks-on-Reserve for the courses with the highest registrations, as well as some of the highest priced textbooks with new titles added each semester. These books are discoverable anywhere you search for library books: RaptorSearch or the MC Library Catalog.